In a semiconductor device assembly, an integrated circuit (IC) die (also referred to as a semiconductor chip or “die”) may be mounted on a packaging substrate. With increasing need for higher performance and density, many integrated circuit packages have been incorporating more integrated components per unit area. Components may be placed closer or stacked together on printed circuit boards to lower device dimension and cost. For example, die-stacking (e.g., face-to-face die stacking, face-to-back die stacking) integration may be required for three-dimensional (3D) multi-die integrated circuit packages to obtain better performance and higher density.
As logic and power density of the 3D packages increase, device cooling has become a more significant concern. Conventional cooling techniques, which depend on heat sinks on the backs of IC dies to transfer heat into streams of forced air, will not be able to meet the needs of power-hungry devices, especially 3D packages that will pack more processing power into less space. The power generated during high volume operation by such devices may reduce the overall cooling efficiency, and create localized regions of high temperature (i.e., hot spots), which may adversely affect the overall performance and reliability of the devices.